Rust is a chemical reaction (oxidation) of iron that occurs over a period of time as the bare metal surface comes in contact with oxygen present in the air or water. Rust "eats" away the metal, rendering it weak and fragile. Therefore, any maneuver that prevents the direct physical contact of iron with oxygen present in air or water will prevent rust formation.
Paint the bare metal with any durable acrylic paint. Do not use water-soluable paints, since they will only worsen the rust. Rust will form underneath this type of paint.
Keep Moisture at Bay
Avoid contact with water or moisture. Know that water has a chemical formula H2O, meaning it has 2 parts hydrogen and 1 part oxygen. Oxygen is responsible for the oxidation of iron and therefore forms rust. Clean all iron items periodically and make sure they are dry.
Coat It With Oil
Use of oil or grease significantly reduces the chances of developing rust in iron. Basically, grease or oil form a protective layer over iron just as paint does and therefore prevents rust formation.
Use stainless steel wherever and whenever possible. Steel is an alloy (metallic mixture) of iron and zinc. Presence of zinc in iron decreases the oxidation of iron, and minimal rust formation occurs.
If rusty metals also contain dirt, they may be a breeding ground for the bacteria that cause tetanus, Clostridium tetani. So taking steps to prevent rust can also help you avoid getting a tetanus infection.